Hand for comptometers.



S. B. LAMKIN.

HAND POR GOMPTOMETBRS.

APPLICATION FILED Nov. 1. 1909.

Patented May 10, 1910.

III',

ANDRE-,v B. GRAHAM co. PMoYc-Llwoenmmins. wAsmNcmN, DC,

s. B. LAMKIN.

HAND POR GOMPTOMEfIERS. kAPPLICATION FILED NOV. 1, 1909.

A 957,221. Patented May 10,1910.

E 3 2 SHEETS--SHEET 2.

2 H.ZW

UNITED STATES PATENT OFFICE.

SAYERS B. LAMKIN, 0F DAWSON, TERRITORY OF NEW MEXICO.

HAND FOR COMPTOMETERS.

ATo all whom it may concern:

Hands for Comptometers; and I hereby declare that the following is afull, clear, and exact description thereof, reference being had to theaccompanying drawings, which form part of this specification.

This invention is a novel device for use with comptometers, or likecalculating machines, to facilitate operations thereon; its object beingto provide a mechanical assistant or hand for the operator wherewith hecan perform operations on the machine with great rapidity, and withabsolute accuracy so far as certain series of repeated key manipulatingoperations are concerned.

The hand is simple, and inexpensive; and will lessen the amount offinger work of the operator; and is readily adaptable for use withvarious kinds and makes of calculating machines.

I will explain the invention as embodied in the hand device illustratedin the accompanying drawings, which is particularly designed and adaptedfor use with a com tometer having ten vertical columns of nine keysnumbered 1 to 9inclusive. Each column having separate calculating andadditive carrying mechanism. The size of hand should be varied tocorrespond with size of comptometer-(the size of calculating machlnedesignated by the number of vertical columns).

I term the device a hand and it consists generally of a plate or frame,provided with a series of rows of holes or sockets in its underside,--corresponding in location and arrangement with the series of rowsof keys in each set in the key-board of the machine,-and with a handleon its upper side by which it can be easily grasped and manipulated bythe operator. The hand is also provided with removable pins which can beplaced in the sockets corresponding to the keys it is desired tosimultaneously depress, and after suitably arranging the pins, theoperator places the hand over the key-board of the machine, and pressesit thereupon, thereby causing the set pins to simultaneously depress thecorresponding Specification of Letters Patent.

Application filed November 1, 1909.

Patented May 10, 1910.

Serial No. 525,814.

keys, and perform at one operation of the hand a number of fingeroperations; the pins performing the work of the operators fingers; andwhen any given series of keys has to be repeatedly operated in makingcalculations, the advantages of the hand over finger' manipulation ofthe keys will be obvious.

I will explain the invention in detail with reference to theaccompanying drawings, and set forth in the claims the essentialfeatures of the invention for which I desire protection.

In said drawings-Figure 1 is a top view of an ordinary comptometerkey-board and showing the hand in operative position thereover, partlyin section and partly in dotted lines. of the hand. Fig. 3 is anenlarged side view of the hand as in operation. Fig. 4 is a perspectiveview of the hand detached; and Fig. 5 is a detail sectional view of thehand.

The hand as shown, comprises a plate l, provided on its under side witha series of rows of sockets la, the number of rows of sockets, and thenumber of sockets in a row, corresponding exactly with the number ofrows of keys, and number of keys in a row, of the key-board of thecomptometer or calculating machine with which the hand is to be used. Asshown there are nine rows of sockets, and ten sockets in a row. Thesockets are numbered correspondingly to the keys of the machine, but inreverse order, and with the digits in large figures in line with thesockets, and the co-digits in smaller figures above and to left of thedigits; see Fig. 2. The complete hand as shown comprises the base plateand its attachments; and ten pins, one for each row of keys. Preferablythe sockets for the even digits may be a sixteenth of an inch deeperthan the sockets for the odd digits, to compensate for the concaved keyson odd digits of the compotometer, and enable the pins, hereinafterreferred to, to be made of equal length.

A set of pins 2 is provided, each adapted to be detachably attached tothe board by having its shank stuck into any of the sockets, as shown.The pins may be of about one and one-fourth inches in length, and havetheir Shanks formed to fit snugly in the sockets so that the pins willnot drop out of place; the

Fig. 2 is a bottom plan view outer portions of the pins may be milled orroughened as indicated at 2, to facilitate their insertion and removalfrom the sockets; and they are preferably provided With rubber tips 2bon their outer ends, so as to cushion their contact With the keys, andlessen shock and noise. The pins may be of aluminum or other suitablemetal and the sockets may be bushed With aluminum or other suitablemetal if desired.

The base is provided at its upper edge, and under side, With a iiange 3,and at its left-hand edge and under side, with a flange 3, which flangesassist in correctly positioning the hand over the key-board of themachine; and when the upper flange 3 is brought against the side of thetop row of keys on the machine, and the side flange against the side ofthe left-hand roiv of keys, all the pins are positioned accurately overthe corresponding keys, (see Figs. 1 and 3) so that by thus locating andthen depressing the hand the proper keys will be simultaneouslyoperated.

The hand has a handle 4 on its top side, by which it can be readilymanipulated.

The utility and mode of using the hand will be clearly understood fromthe following examples.

Operation: The hand is not designed to be used in the ordinary simplemultiplying and dividing operations on the comptometer, although it canbe used for any example large or small; but it is part-icularly adaptedfor long multiplication and division computations, such as inrailroadoperating statements, in ascertaining cost per train mileagainst operating expenses, and their hundreds of sub-accounts Where acommon divisor is used; or in mining calculation, in ascertaining thecost per ton of coal mined against the various operating expenses; orcost per ton of coke made against the various expenses. In suchaccountings the divisors are frequently in the hundreds of thousands,and can very seldom be simultaneously reached With the fingers, andnever ivith swiftness and accuracy; and for this reason special ruleshave been devised for accomplishing division on the comptometer, whenthe divisor is of four or more digits, and even their Work is very slowand tedious. YVith my hand however adivisor of ten places can be Workedjust as rapidly and accurately as a divisor of two digits. it ispreferable to figure such division computations b v using a reciprocaland multiplying, as multiplication can be done on the comptometer fasterthan division, and the hand is invaluable in such Work. As an example ofthe utility of the hand assume the divisor to be 2,236,217.48 and thereciprocal is 0000004471836961; set the reciprocal (4471836961) in thehand as per rules governing the comptometer (see Fig. 2) and set thedecimal point on the register as usual-then proceed with multiplicationas usual, assuming the items to be as follows, viz:

Efvpcase 1' tems. Oost.

The reciprocal set into the hand forms the multiplicand and the expenseitems the multiplier. The first item computes a cost of 7 mills againstsay repairs to track; next item computes .0003 against repairs tobridges, and so on arriving at a total cost of .0154 against sayoperating account maintenance of Way. Generally only four decimalfigures are shown in a statement; but to be absolutely accurate theextra decimals may be figured to determine the correct fourth decimal.1n the foregoing example the decimals are carried to the extreme of tencounting digitsI in the reciprocal (16 places) to shoiv what the handcan accomplish in one shift. Eight significant terms in the reciprocalis what is generally used, but l can operate up to ten digits as readilyas any less number. Of course for smaller key-boards, the chand7 couldbe made smaller, the feature thereof being that it is provided withsockets corresponding in number and arrangement With the keys of thekey-board of the machine; and With a pin for each row of sockets. Afterthe operator sets up the reciprocal on the hand by adjusting the propernumber of pins in the proper rows; all he has to do in entering thereciprocal on the machine, is to press the hand down upon the key-boardand he can perform this operation rapidly, Without any mental Worry asto its accuracy, and Without tiring his lingers, and With no possibilityof error if he accurately sets the pins in the hand at the outset.

In Working division or multiplication, the operator should set up thedivisor or multiplicand, respectively, in the hand and proceed in theusual manner. For example, if the quotient of 382561.47 and 897449 berequired, set up the multiplicand in the hand, beginning with 3 at theright and Working to the left; this When inverted Will make the 382 fallover the first three columns to left of the machine. Strike the keyseight times, with the handg7 then move hand one column to right, whichwill place the partition side between the first two columns to left ofmachine, and strike nine times. Then move hand one column to right, andstrike seven times; etc. until all digits of multiplier have been used;pointing ofi' in the usual way. Since multiplication is easier toaccomplish on the comptometer than division it is often advantageous towork up a set of division computations by multiplication and when onedivisor is common to several or numerous dividends, such as ascertaining(in railroad work) cost per freight train mile against the hundreds offreight operating expenses, it is an easy matter to find a reciprocal,or how many times the divisor is contained into $1.00 and multiplyingsuch reciprocal by the various expenses. After finding the reciprocalset it up in the hand as already explained, set your decimal pointer oncomptoineter behind the required decimal and use figures to left of suchpointer. If cost is required to four places, it is not necessary to workout your reciprocal to more than six significant terms. In corporationaccounting, however, many straight division computations are required oflong dimensions such as ascertaining percentage of operating expenses toearnings, etc. F or example say the earnings for a certain periodamounts to $318,198.65 against operating expenses amounting to$237,548.72. Strike ott' the dividend on machine according to the digits(large figures) beginning at the extreme left, causing 237548.72 toappear on the register. Set up the divisor in the hand according to theco-digits (small figures) beginning from extreme right column of handand working to left, which when inverted will throw the 318 directlyover the 237. Since 318v is not contained into 237 move the hand onecolumn to right letting partition board slip between first and secondcolumns of keys, then 2 being the first figure to left of' hand striketwice with the hand and keep on striking until the number of strokesagree with that figure which was formerly 2," then, without shifting tonext column, keep on striking until the register shows a number smallerthan 318; then shift to the next column which will place partition boardof hand between the second and third columns of comptometer, and proceedas before; and so on through the series, and the register will show.7465219 (quotient)- 29739565 (remainder)--or .7465 answer. It is ofcourse not necessary to carry out operations to such extremes forpractical purposes but they should be carried out six decimals forabsolute accuracy. An idea of how much time may be saved by using thehand in such computations can be gained by working out this example on aten column comptometer to 7465422, and applying special rule laid downfor division when divisor is over four places; it takes aboutone-hundred and eleven finger operations to work the example out sevenplaces. lVith the hand it will require only thirty strokes. Time is alsosaved in manipulating the fingers for new trial divisors. When using thehand the divisor being set up, no manipulating is necessary. Anothergreat advantage in using the hand is that it is not so trying on theeyes and brain or' the operator, as all he has to think about is howmany times to strike; and since he does not have to manip ulate the keysin any way, he can work out computations in multiplication and divisionvery rapidly.

Having described my invention what I claim as new and desire to secureby Letters Patent thereon is:

1. A key-operating attachment for comptometers and the like, comprisinga plate provided with a plurality of' sockets on one face correspondingin arrangement with the keys of the machine, and a smaller number ofadjustable pins adapted to be placed in any of said sockets and wherebypredetermined keys of the machine may be simultaneously operated bymanually placing the plate over the keys and depressing the same.

2. A key-operating attachment for comptoineters and the like comprisinga hand consisting of a plate provided with a series of rows of socketson one face corresponding in arrangement with a set of keys on amachine, and depending flanges on its under side whereby the plate maybe properly positioned over the keys; with adjustable pins adapted to beremovably engaged in any of said sockets whereby the predetermined keyson the machine may be simultaneously operated by placing the plate overthe keys and depressing same.

3. A key-operating attachment for comptometers and the like comprising aplate having a plurality of rows of sockets on its under sidecorresponding in arrangement with the keys on the machine, said socketsbeing numbered correspondingly with the keys, and depending flanges onthe lower face and top and side of the plate whereby it may be correctlypositioned over the keys previous to depression thereof; with a set ofremovable pins each adapted to be detachably secured in any one of thesockets.

4. A key-operating attachment for comptometers and the like comprising amechanical liand7 having a plurality of rows of sockets on its underside corresponding in number and arrangement with the keys on themachine, said sockets being numbered correspondingly with the keys; ahandle on the top of the hand opposite the sockets whereby it may bemanipulated by hand, and means on the lower face of the hand whereby itmay be correctly positioned over the keys previous to depressionthereof; with removable pins adapted to be detachably secured in any ofthe sockets.

A key-operating attachment for comptometers and the like comprising amechanical hand having a plurality of sockets on its under sidecorresponding in arrangement with the keys on the machine; a set ofremovable pins each adapted to be detachably secured in any of thesockets, said pins having rubber tips on their outer ends, and thesockets corresponding to the concaved keys on the comptometer beingshallower than the other sockets.

6. A manually operable key-operating attachment for comptometers and thelike comprising` a plate having rows of sockets on its under sidecorresponding in arrangement with the keys on the machine, said socketsbeing numbered correspondingly-

